Lubricating oil containing an antioxidant



i atentecl Feb. 22 i945;

UNITED STATES ATENT OFFICE LUBRICATING OIL CONTAINING AN ANTIOXIDAN Tware No Drawing. Application December 5, 1944, Serial No. 566,772

4 Claims.

This invention relates to lubricants and other organic materials subjectto deterioration in the presence of oxygen, and it relates moreparticularly to mineral lubricating oil compositions for use ascrankcase lubricants for internal combustion engines containing additionagents suitable for retarding the deterioration of such oils and forlowering the pour point of the same.

In accordance with the present invention a new class of organicderivatives of boric acid are described which are particularly useful asadditives for mineral lubricating oils used in internal combustionengines, in which they act as inhibitors of oxidation and deposition ofvarnish on hot metal surfaces and as agents for substantially reducingthe pour point of the base oil. They are particularly useful ininhibiting the normal corrosiveness of the oil when in contact withcopper-lead, cadmium-silver and other similar bearings now widely usedin automotive engines. these compounds are likewise suitable asantioxidants in organic materials generally where the organic materialis known to be susceptible to deterioration in the presence of oxygen.

It has been proposed in the art to use various esters of boric acid,such as tributyl borate, triamyl borate, trilauryl borate, triphenylborate and the likes as additives for inhibiting the corrosiveness oflubricating oils toward hard metal alloy bearings. It has been found,however, that when alkyl borates or aryl borates with only short alkylside chains are used as additives for oils, the ester is hydrolyzed bymeans of moist air, with the result that boric acid is precipitated inconsiderable quantities from the solution as a solid precipitate. Bycomparison, the additives of the present invention are [practically freefrom a tendency to hydrolize in this manner.

The new class of antioxidant compounds are long chain alkylated arylborates, and those which are especially effective are the wax-alkylatedphenyl borates. The new class of additives may be defined more preciselyby the general formula (RAT) mHnBOB where Ar is any aryl nucleus, e. g.,a benzene, biphenyl or naphthalene nucleus, R represents at least oneopen chain alkyl radical, all of such radicals containing a total of atleast 16 carbon atoms, m is an integer from 1 to 3, n is 0, 1 or 2, andm+n equals 3. The above formula is intended to include also compounds inwhich various substituent atoms or groups may be attached to thearomatic nucleus or to the side chain, such as alkyl, aryl, carboxyl,hydroxyl, alkoxy, aroxy, sulfhydryl, nitro, ester, keto, thicether,amino or aldehydo groups, halogen atoms, etc.

A highly preferred class of compounds are the wax-alkylated phenylborates, which may be readily obtained by first preparing a wax-alkyl-'ated phenol, as by reacting phenol with a chlorinated wax, and thenreactingthe wax-alkylated phenol with boric acid. Compounds of this typewhich contain two or more wax chains on the phenyl nucleus arepreferred, Various ratios of wax-alkylated phenol to boric acid may beused in the preparation, ranging from 1:2 to 3:1. It should beunderstood that more than one phenyl group may be attached to a singlewax chain, as when a wax containing chlorine atoms at a number of pointsin the chain is reacted with phenol to produce a wax chain containingseveral phenol substituent groups, and that compounds so produced areintended to be included within the scope of the above general formula.

Alkyl phenols whose borate esters may be employed in the presentinvention include: Wax alkylated phenol, wax alkylated naphthol, waxalkylated cresol, cetyl phenol, octadecyl phenol (stearyl phenol),di-tert.-octyl phenol, isohexadecyl phenol, and Cm-Czo branched chainalkyl phenols obtained by alkylating phenol or a cresol with a refinerybutene polymer oil. Borates of the corresponding alkyl phenol sulfidesmay also be employed.

Generally, the additives of the present invention are mostadvantageously blended with lubricating oil base stocks inconcentrations between the approximate limits of 0.02% and 5.0% andpreferably from 0.5% to 2.0%, although larger amounts may be used forsome purposes. The exact amount of addition agent required for maximumimprovement depends to a certain extent on the particular products used,the nature of the lubricating oil base stock, and the general operatingconditions of the engine in which the lubricant is to be used.

A number of examples of the preparation of the new compounds of thepresent invention and of the intermediates used in the preparation ofsuch compounds will be described in detail, and data PRODUCTION OFCI-EORINATED WAX EXAMPLE 1 1 kg. of refined paraffin wax (M. P. 122 F.)was placed in a reaction flask and the wax melted over a hot plate. Whenthe temperature of the melted wax reached 240 F. the hot plate wasremoved and the flask placed on a balance and chlorine gas passed intothe wax at such a rate that the temperature remained about 200 F.throughout the entire chlorination process. When the weight hadincreased by a little more than 198 g. the flow of chlorine was stoppedand dry nitrogen was passed in to remove the excess chlorine and H01.This was continued for about 2 hrs. The resulting product (product I)was found to contain 17.46% chlorine.

EXAMPLE 2 2 gallons of chlorinated wax, obtained by chlorinatingsemi-refined wax (M. P. 118 F.) at 200 F. by a process similar to thatdescribed in Example 1 and containing 13.5% chlorine when meltedcompletely, was poured into a round bottomed flask. This was placed on asteam bath and nitrogen blown through for about 2 hours. The product wasfound to contain 12.83% chlorine (product HA).

1 gallon of product IIA after standing for about weeks was found to bemostly liquid at 131 C. The liquid portion was siphoned off into aseparate vessel, This liquid portionwas found to contain 13.60% chlorine(product IIB).

PRODUCTION OF WAX PI-IENOLS EXAMPLE 3 50-0 grams of chlorinated waxprepared as in Example 1 (product I) was placed in a 3-necked flask withstirrer. reflux condenser and thermometer. 70.5 grams of phenol wasadded, and a smaller flask containing grams of AlCls was attached to oneneck of the reaction flask by means of Gooch tubing. Thephenol-chlorinated wax mixture was heated to 65 C. and maintained atthis temperature during the addition of the AlCls over a 1 hour period.The mixture was then slowly heated to 150 C. over a period of 1 hours;During this heating HCl was evolved in large quantities. Heating wascontinued for 3 hours more at 150 C. and the mixture Was then cooled toabout 30 C. and 1 liter of petroleum naphtha (B. P. mil-240 F.) wasadded. The solution was poured into water and acidified with HCl. Themixture was shaken thoroughly to remove the AlCls. It was necessary toadd isopropyl alcohol to break the emulsion. The mixture was washedseveral times with water and the upper layer was then distilled toremove the solvent. The distillation Was begun at atmosphericpressure,then moderate vacuum was applied carefully when the vapor temperaturerose above 100 C. After the bath temperature had risen to 250 C. thesolution was distilled at about 1.5 mm. pressure until the temperatureof the bath had reached 225 C. The residue weighed about 465 grams.(Product IIIA.)

312.3 grams of product IIIA was distilled to remove the unreactedchlorinated wax. The dis- 4 tillation was carried out at less than 1 mm.pressure and continued until the distillation temperature rose to 260 C.The residue weighed 276.8 grams. (Product HIB.)

EXAMPLE 4 500 grams of chlorinated wax (product IIA) was placed in areaction flask with stirrer and return condenser and 56.4 grams ofphenol was added. The mixture was heated to- 65 C. and then over aperiod of one hour 15 grams of AlCla was gradually added from anErlenmeyer flask connected to a side neck with Gooch tubing. The mixturewas slowly heated at C. and

maintained at that temperature for 3 hours, after which it was partlycooled and 1 liter of naphtha was added. The naphtha solution was washedthree times with water and dried over anhydrous CaClz. The solvent wasstripped ofi at atmospheric pressure. The temperature was raised to 2500., moderate vacuum being first applied and then high vacuum (less than1 mm.) to remove the unreacted chlorinated wax as a distillate until atemperature of 260 C. 'was reached. The residue weighed 342 grams.(Product IV.)

EXAMPLE 5 560 grams of chlorinated wax (product I) was placed in areaction flask equipped with stirrer, return condenser, and thermometerand 67 grams of phenol was added. The mixture was heated to 65 C. and 15grams of anhydrous AlCh was added gradually over a period of 1 hour,employing the same technique as in previous examples. The flask wasgradually heated to 150 C. and held between 150 and C. for over 3 hours.The flask was allowed to cool partially and 1 liter of naphtha wasadded. The mixture was poured into a separatory funnel, allowed .tostand EXAMPLE 6 500 grams of chlorinated wax (productIIA) was placed ina reaction flask with stirrer, reflux condenser, and thermometer and56.4 grams of phenol was added. The mixture was heated to 65 C. and 15grams of anhydrous AlCla was.

added in small proportions over a 'period of 1 hour. The mixture wasgradually heated to 150 C. and held at 150-160 C. for over 3 hours. Themixture was allowed to cool partially and 1 liter of naphtha added. Thesolution was poured into a separatory funnel, allowed to stand overnightand washed twice with water and dried over CaClz. The solvent and asmall amount of water present were removed by distillationunder moderatevacuum until a bath temperature of 250 C. was attained. The residue wasdissolved in naphtha and filtered through I-Iyflo. The solvent andunreacted materials were distilled off under lessthan 1 mm. pressure upto a distilling temperature of 230 C. The residue weighed 400 grams.(Product VI.)

EXAMPLE 7 500 grams of chlorinated wax (product 11B) was placed in areaction flask with stirrer, return condenser, and thermometer, 60 gramsof phenol was added and the whole heated to 65 C. To this solution 15grams of anhydrous AlCla was added over a period of hour. The mixturewas gradually heated to 150 C. and held at that temperature for 4 hours,after which 1 liter of naphtha was added. The solution was decanted to aseparate flask and NH3 gas passed in for A.; hour to decompose any A1013present. Air wa blown in to remove the excess of NH3. The solution wasfiltered and the volume of the filtrate then reduced by vacuumdistillation until 605.8 grams of residual naphtha solution remained.

The residual naphtha solution was Washed with dilute HCl and three timeswith Water, and then dried by refluxing with a water trap. The solventwas removed by distilling in vacuum over a boiling water bath, theresidue weighing 534 grams. (Product VII.)

PREPARATION OF WAX PHENYL BORATES In Examples 8 to 15 will be describedseveral preparations of wax phenyl borates, by reacting the wax phenolsprepared as described above with boric acid in various proportions andunder varying conditions of procedure.

EXAMPLE 8 95.5 grams of wax phenol (product IIIA) was placed in areaction flask and 500 cc. of xylene added. A stirrer, thermometer, andreturn condenser with trap were attached and the mixture refluxedseveral hours to remove any water which may have been present. Therefluxing was stopped and '7 grams of powdered H3BO3 was added while themixture was still hot. There was considerable reaction immediately withliberation of water. The mixture was refluxed overnight, then cooled andfiltered. The solvent was removed from the filtrate by moderate vacuumand heated to 250 C. in a metal bath. The residue weighed 105 grams.(Product VIII.) This product was an amorphous, dark colored solid,somewhat gelatinous when cooled.

EXAMPLE 9 100 grams of wax phenol (product IV) was dissolved in 500 cc.of toluene and placed in a reaction flask equipped with stirrer, returncondenser and water trap. The solution was refluxed to remove any waterwhich may have been present. 10 g. of HsBOs was added and the mixturerefluxed overnight. The solution was filtered from excess H3303 and thesolvent distilled from the product at a pressure of 1 mm. until the bathtemperature reached 190 C. The residue weighed 103.6 g. (Product IX.)

EXAMPLE 10 100 g. of wax phenol (product 1113) was dissolved in 500 cc.of toluene and placed in a reaction flask equipped with stirrer, returncondenser and water trap. The solution was refluxed to remove any waterwhich may have been present. 3.56 g. of HsBOa was added and the mixturerefluxed for 6 hours, water formed during the reaction being removedthrough the trap. All of the H3BO3 dissolved with the exception of a fewcrystals on the bottom of the flask. The solution was placed in aClaisen flask and the solvent removed by distillation under moderatevacuum up to an oil bath temperature of 190 C. The residue weighed 101.1g. (Product X.)

EXAMPLE 11 In the same manner as in Example 9,

200 grams of wax phenol (product V) was dissolved in 750 cc. of mineralspirits having a boiling range of 300 to 410 F. and placed in a reactionvessel equipped with stirrer, thermometer, return condenser, and watertrap. 14.3 grams of H3303 was added. The mixture was heated to 155 F.and held at this temperature overnight. The solution was filtered withthe aid of Hyflo and the solvent partially removed by distillation undervacuum, then 800 grams of a refined paraflinic type mineral lubricatingoil of S. A. E. 20 viscosity grade was added and the remainder of themineral spirits removed by further distillation under house vacuum(150-200 mm. pressure) using a maximum bath temperature of 290 C. Amaximum vapor temperature of 142 C.was reached. The residual oilsolution was further treated by heating it for 4 /2 hours at 150 C. with15 grams of boric acid, a stream of nitrogen being blown through themixture at the same time to facilitate removal of water. A filter aid(Hyflo) was added and the mixture filtered to give a clear oilconcentrate containing about 20% of wax phenyl borate. (Product XII.)

EXAMPLE 1.3

200 grams of wax phenol (product VI) was dissolved in 1 liter of mineralspirits having a boiling range of 300 to 410 F. and placed in a reactionflask containing 12 grams of HaBOa. A stirrer, thermometer, and returncondenser with water trap were attached and the mixture refluxed toremove water. The mixture was maintained at 150 C. overnight withoutrefluxing and then filtered with the aid of Hyflo. The mineral spiritswas partially removed by vacuum distillation (150-200 mm.) 600 grams ofS. A. E. 20 mineral lubricating oil was added and the vacuumdistillation was continued. The distilling temperature rose to a maximumof C. with a bath temperature of 240 C.

The oil solution was further treated by heating it for 4 /2 hours at C.with 15 grams of boric acid, a stream of nitrogen being blown throughthe mixture at the same time to facilitate removal of water. A filteraid (Hyflo) was added and the mixture filtered to give a clear oilconcentrate containing about 25% of wax phenyl borate. (Product XIII.)

EXAMPLE 14 300 grams of Wax phenol (product VIIB) was placed in areaction flask equipped with stirrer,

. thermometer, and return condenser with water aeea eic EXAMPLE 15 '200grams of waxphenol (product VIIB) and 1 liter of toluene'were placed ina reaction flask equipped with stirrer. thermometer, and returncondenser with water trap.

10.3 grams of s Tabl ll Borate Ester Amount of PrecipitationOcigadlefiyl borate (Product A voluminous precipitate-small -HaB'O3 wasadded and the mixture stirred and l T rt.-Octylphenyl borate Volummo s rc it t o d refluxed over the week-end. All of the H3803 rioduct XVI). T1p Mm M W had disappeared. The toluene was removed by 33333; r 3 -Tg'gggg ggg gi moderate vacuum distillation over a water bath Product XI.No precipitate. and finally under high vacuum. The residueggggggggkaghazy weighed 194.5 grams. (Product XV.) Product XIV Slightpowdery precipitate. In t following table are summarized some Product XVi gl Solutwn and Slight fine p p a 0. t e more pertinent data relatingto the WaX Tricthylborate Immediate voluminous precipitate. phenylborate products whose preparation has Tmmylbmte been described above.

Table I Per cent Acetyl M01. Wt.

Per cent Wax Phenol/ Wax/Phenol 1 1n No. of from Product No. Cl 113x01Ratio Wax Wax Acetyl Hzalg rb 1;(a)t1o 7 Phenol Phenol N o.

. EXAMPLE l6 POUR'POINT TESTS Tertiary octyl phenol was prepared byalkyla- 30 EXAMPLE 1 tion of phenol with diisobutylene. 206 grams oftertiary octyl phenol was dissolved in 824 grams of S; A. E. gradesolvent refined paraffinic type mineral lubricating oil and treated with61.8 grams of boric acid. The mixture was heated at 150 C. for 5 hourswith stirring, nitrogen being blown through the mixture to facilitatewater removal. The product was then filtered using Hyflo filter aid, togive a clear oil concentrate containing of tertiary octyl phenyl borate.(Product XVI.)

EXAMPLE 17 A solution of 27.0 grams (1 mol. proportion) of commercialstearyl alcohol (octadecyl alcohol) in 810 grams of S. A. E. 20 gradeparaffinic type mineral lubricating oil was treated with 20.6 grams (3mol. proportions) of boric acid. In essentially the same manner as inExample 16 the mixture was heated and stirred and blown with nitrogenfor 5 hours at 150 C. and then filtered, giving a clear oil concentratecontaining 25% of tri-octadecyl borate.

MOIST AIR TEST EXAMPLE 18 In the following series of tests, water-washedairwas passed through oil solutions containing 1% each of various borateester products to determine the efiect of such .moist air in hydrolyzingthe ester and precipitating the bOIic acid from the oil solution. Foreach test 1% of the ester was dissolved in a base oil consisting of arefined parafrlnic type lubricating oil of 20 viscosity grade, and 100cc. of such solution was placed in a suitable vessel. Air was thenbubbled through a bottle containing water and then through the oilsolution at a rate of 4 to 7 cc. per second for a period of two days ineach test, the apparatus being kept at room temperature. The resultsgiven in Table II show the amount of precipitate observed as the resultof the hydrolysisof the ester. A number of alkyl and alkaryl esters ofboric acid have'thus been compared with the waX-phenyl borates producedin the processes described above.

Measurement was made of pour points of the various wax phenyl borateproducts in a clay finished Pennsylvania neutral distillate lightlubricating oil stock with a normal pour point of +30 F. 0.5% and 1%solutions were thus tested. The results are shown in Table III.

Table III Pour Point of Solution in Oil Product No.

VIII. 35 -ss 1x. -35 5 -25 -35 +10 0 -35 -5 +15 -10 +15 INDIANA LIFETESTS EXAMPLE 20 Blends .of lubricating oils containing additivesprepared in accordance with the present invention were submitted to thestandard Indiana oxidation test, described in S. A. E. Journal, vol. 34,page 167, (1934). 0.5% of borate ester was present in each oil blend.Theresults are shown in Table IV. The values given represent the numberof milligrams of sludge formed from 10 g. of oil at the end of variousperiods during which the test was run. The base oil used in each casewas well refined, solvent extracted paraflinic typemineral lubrieatingoil of S. A. E. 20 grade. A

. During each test the varnish forming tendency of each oil blend wasalso determined in the following manner: In each oil sample tube a glassplate about 3" by 1" was placed. At the end of the 96 hour period'theplate was removed, washed with naphtha; airdried and then weighed todetermine the amount'ofyarnish' deposited. The milligrams ofvarnish:obtained in each test are also given in Table- IV.

Table IV [Sludge (Mg/l gfof oil)]i on 24 4s 72 96 Indiana Mg.

Hours Hours Hours Hours Hour 1 Varnish Base Oil 0 0 16 55 63 3. 6 Base0il+Product VIII 0 0 0 Trace 96 0.1 Base Oil-l-Product IX 0 Trace Trace43 78 2. 3 Base OiH-Product X. 0 0 Trace 57. 8 76 0.8 Base Oi1+ProductXL 0 Trace Trace 22. 4 83 1. 2 Base Oil+Product XIL 0 Trace 8. 1 68. 773 3.1 Base Oil-l-Product XIII. 0 0 Trace 48. 4 77 3. 3 Base Oil+ProductXIV"... 0 Trace Trace 66. 0 76 2. Base 0il+Product XV 0 Trace Trace 35.8 79 3.1

1 Hours to form 10 mg. of sludge (determined by interpolation).

BEARING CORROSION TESTS EXAMPLE 21 Blends of the wax phenyl borateproducts pre pared by the methods of the foregoing examples in alubricating oil base consisting of a Well refined solvent extractedparaffinic type mineral lubricating oil of S. A. E. viscosity grade, theblends containing 0.5% and 1.0% of the additive, and a sample of theunblended base oil, were submitted to a corrosion test designed tomeasure the efiectiveness of the products in inhibiting thecorrosiveness of a typical mineral lubricating oil toward the surface ofcopper-lead bearings. Th test was conducted as follows:

500 cc. of the oil was placed in a glass oxidation tube (13" long and 2diameter) fitted at the bottom with a A bore air inlet tube perforatedto facilitate air distribution. The oxidation tube was then immersed ina heating bath so that the oil temperature was mantained at 325 F.during the test. Two quarter sections of automotive bearings ofcopper-lead alloy of known weight having a total area of sq. cm. wereattacked to opposite sides of a stainless steel rod which Was thenimmersed in the test oil and rotated at 600 R. P. M., thus providingsufiicient agitation of the sample during the test. Air was then blownthrough the oil at the rate of 2 cu. ft. per hour. At the end of eachfour-hour period the bearings were removed and were washed with naphthaand weighed to determine the amount of loss by corrosion. The bearingswere then repolished (to incrase the severity of the test) reweighed,and then subjected to the test for an additional four-hour period. Thecumulative weight losses of all the bearings used in a given test at theend of the various four-hour periods are given in Table V.

Table V The lubricating oil base stocks employed in the blendedlubricating oils of this invention may be straight mineral lubricatingoils, or distillates derived from paraffinic, naphthenic, asphaltic ormixed base crudes, or, if desired, various blended oils may be employedas well as residuals, particularly those from which asphalticconstituents have been carefully removed. The oils may be refined byconventional methods using acid, alkali and/or clay or other agents suchas aluminum chloride, or they may be extracted oil produced, forexample, by solvent extraction with solvents of the type of phenol,sulfur dioxide, furfural, dichloro ethyl ether, nitrobenzene,crotonaldehyde, etc. Hydrogenated oils or white oils may be employed aswell as synthetic oils prepared, for example, by the polymerization ofolefins or by the reaction of oxides of carbon with hydrogen or by thehydrogenation of coal or its products. In certain instances crackingcoil tar fractions and coal tar or shale oil distillates may also beused. Also, for special application, animal, vegetable or fish oils ortheir hydrogenated or voltolized products may be employed, either aloneor in admixture with mineral oils.

For the best results the base stock chosen should normally be that oilwhich without the new additives present gives the optimum performance inthe service contemplated. However, since one advantage of the additivesis that their use also makes feasible the employment of lesssatisfactory mineral oils or other oils, no strict rule can be laid downfor the choice of the base stock. Certain essentials must of course beobserved. The oil must possess the viscosity and volatilitycharacteristics known to be required for the service contemplated. Theoil must be a Cumulative Bearing Weight Loss (mg/25 sq. cm.

surface) Cone.

Oil Blend percent 4 8 12 Hours Hours Hours 24 Hours Hours Base OilBasebOil-i-Product VIII. o

Base Oil+Product IX".

satisfactory"solvent for the additive, although in some cases auxiliarysolvent agents may be used. The lubricating oils, however they have beenproduced, may vary considerably in viscosity and other propertiesdepending upon the particular use for which they are desired, but theyusually range from about 40 to 150 seconds Saybolt viscosity at 210 F.For the lubrication of certain low and medium speed Diesel engines thegeneral practice has often been to use a lubricating oil base stockprepared from naphthenic or aromatic crudes and having a Sayboltviscosity at 210 F. of 45 to 90 seconds and a viscosity index of 0 to50. However, in certain types of Diesel service, particularly with highspeed Diesel engines, and in gasoline engine service, oils of higherviscosity index are often required, for exampleup to 75 or 109, or evenhigher, viscosity indexi" In addition to-the materials to be addedaccordingito the present invention, other agents may also. be used suchas dyes, pour depressors, heatgthickened fatty oils, sulfurized fattyoils, org-ano metallic compounds, metallic or other soaps, sludgedispersers, antioxidants, thickeners, viscositylndeximprovers, oilinessagents, resins, rubber, olefinzpolymers, voltolized fats, voltolizedmineral oils, and/or voltolized waxes and colloidal solids such asgraphite or zinc oxide, etc. Solvents and assisting agents, such asesters, ketones, alcohols, amides, nitriles, amines; aldehydes,halogenated or nitrated compounds and the like may also be employed.

Assisting agents which are particularly desirable for. reducing foam andfor plasticizing concentrated oilsolutions of the additives are thehigher alcohols having eight or more carbon atoms and preferably12to 20carbon atoms. The alco hols may-be saturated straight and branched chainaliphatic alcohols such as octyl alcohol, CsI-InOH,--lauryl.alcohol,C12H25OH, cetyl alcohol, C1eH33OH, stearyl alcohol, sometimes referredto as octadecyl-alcohol, C18H37OH,-a-nd the like; the correspondingolefinicalcohols such as oleyl' alcohol; cyclic-alcohols, such asnaphthenic alcohols; ,and aryl substituted alkyl alcohols, for instancephenyl octyl alcohol, or octadecy1 benzyl alcoholor. mixtures of thesevarious alcohols, which may be pure or substantially pure syntheticalcohols. One may also use mixed-mate urally occurring alcohols suchasthose found in- WOOL fat. (which is known to contain a substantial'percentageof'alcohols having'about 16 to 18 In addition to beingemployed in crankcase.

lubricants and in extreme pressure lubricants, the additives of thepresent invention may also be used in industrial lubricants, processoils, en'- 12 gine flushing oils, turbine oils, insulating andtransformer oils, steam cylinder oils, slushing and rust preventivecompositions, and greases. Also their use in motor fuels, Diesel fuelsand kerosene is contemplated. Since these additives exhibit antioxidantproperties and are believed also to possess ability to modify surfaceactivity, they may be employed in asphalts, road oils, waxes, fatty oilsof animal or vegetable origin, soaps, and plastics. Similarly, they maybe used in natural and synthetic rubber compounding both asvulcanization assistants and as antioxidants, and

where Ar is an aryl nucleus, R represents at least one alkyl radical,the alkyl radicals containing a total of at least 16 carbon atoms, m isan integer from 1 to 3, n is 0, 1 or 2, and m-l-n equal 3.

2. A composition ofmatter consisting essentially of a minerallubricating oil and an oxidation inhibiting proportion of a compound ofthe formula (RAY) mHnBO3 where Ar is an aryl nucleus, R represents atleast one-alkyl radical, the alkyl radicals containing a total of atleast 16 carbon atoms, m is an integer from 1 to 3, n is 0, 1 or 2, andm-i-n equal 3.

3. Acomposition of matter according to claim 2 in-which R of the formulais a wax radical and Ar is abenzene nucleus.

4.. A:composition of matter consisting essentially of a mineral;lubricating oil and an oxida tion inhibiting quantity of a wax alkylatedphenyl borate.

LAWRENCE T. EBY. LOUIS A. MIKESKA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,154,098 Loane et al Apr. 11,1939 2,260,337 Prescott Oct. 28, 1941 2,260,338 Prescott Oct. 28, 19412,300,006 Prescott Oct. 27, 1942 2,312,208 Clayton Feb. 23, 19432,316,903 VanEss Apr. 20, 1943 2,326,496 ReiiT Aug. 10, 1943 2,333,871Lincoln Nov. 9, 1943 2,346,157 Farrington Apr. 11, 1944 2,357,287 Reiffl Sept. 5, 1944 2,383,605 Lieber Aug. 28, 1945

